#include <iostream>
#include <map>


int main(int argc, char const *argv[])
{
    std::map<int, int> v;
    v.insert({1, 2});
    v.insert(std::pair<int, int>(2, 3));
    v.insert(std::map<int, int>::value_type(3, 4));
    v.insert(std::make_pair(4, 5));
    for(auto it = v.begin(); it != v.end(); it++) 
    {
        std::cout << it->first << " : " << it->second << "\n";
    }

    auto value = v[0];
    std::cout << value << "\n";
    return 0;
}
